The invention relates to rotary railroad car couplers and drawbars, wherein the individual cars of a train are separately rotated to an inverted position where the contents of the car falls, by gravity, into a hopper or bin which is positioned to receive the material being dumped from the car. During the dumping operation, the cars are maintained in coupled relation.
U.S. Pat. No. 4,128,178 is typical of the many patents relating to rotary F-type couplers, wherein the shank of the coupler is pinned to a cylindrical connector which is rotatable in a similarly shaped recess that is formed in a yoke or housing which is secured to a subsill that is located at each end of a railroad car. Such couplers employ some type of a draft gear or cushioning device for dampening forces imparted to the coupler during operation of a train which is made up of railroad cars with rotary F-couplers.
U.S. Pat. No. 5,096,075 is typical of the many patents relating to rotary drawbars which are called "slackless", because they to not employ any cushioning devices. Rather, they use a system of tapered shims or wedges to take up any slack between the various parts of the rotary mechanism of the drawbar.
Two important criteria must be met in the design of a rotary coupler or drawbar. Firstly, they must be able to rotate freely about their longitudinal axes and, secondly, they must be able to rotate a limited distance in a vertical plane, called vertical angling, to compensate for relative vertical movement between a pair of adjacent railroad cars, as they move along a trackway. Movement, other than vertical angling between adjacent cars, is compensated for by a combination of the rotational and angling characteristics of the drawbar or coupler. The rotation of a drawbar or railroad car coupler about its longitudinal axis, is not problematical. Nor is vertical angling of such rotary devices, when they employ some type of cushioning mechanism, since there is usually enough slack and resiliency to allow vertical angling.
However, the situation is different in a slackless rotary device, where any slack or resiliency in the device is undesirable and eliminated. There is a problem of vertical angling in a slackless rotary drawbar or railroad car coupler. The '075 patent teaches one solution to this problem by the provision of a pair of special bearing blocks 3 and 32 in combination with a slackless, oblong pin hole 16, as best seen in FIGS. 1 and 2. The invention is directed to a different solution to this problem of vertical angling in a slackless, rotary device.
Briefly stated, the invention is in a slackless, rotary connection which is used between adjacent railroad cars that are movable along a fixed trackway. The connection comprises a housing for a special connector to which the butt end of a railroad car coupler head or drawbar is fastened by means of a cylindrical pin. The connector is generally ball shaped and designed to swivel freely in a spherical recess which is formed in the housing. This particular rotary connection resembles a ball and socket type swivel joint which allows both rotation and angling, as previously described.
Another aspect of the invention is the provision of a wedging mechanism between the front follower and butt end of the shank of the coupler head or drawbar, to take up any slack which develops between these two components during operation of the rotary connection.